crystal: fix build with newer versions of clang

[reckenrode]

Description of changes

Crystal requires linking libc++abi when building with newer versions of clang. See #166205.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.11 Release Notes (or backporting 23.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[peterhoeg]

Are you able to test if there is any issues as a consequence of the llvm build on nixos too?

[reckenrode]

Are you able to test if there is any issues as a consequence of the llvm build on nixos too?

It shouldn’t affect standard Linux. I reworked the patch to check for clang and libc++, so it should work with pkgsLLVM, but cpio failed to build when I tried it (with LLVM 16).

[reckenrode]

This is failing on staging-next: https://hydra.nixos.org/build/239425775. #263535

[toonn]

LGTM

When rebased on staging-next the commit indeed fixes the crystal build.

On master the commit also builds, but, when editing the crystal derivation to use llvmPackages_16.stdenv (because crystal is not overridable) a segmentation fault occurs when running the built crystal compiler (this happens during the build). On master without the commit, but, changing the derivation to use LLVM 16 stdenv the segmentation fault does not happen and instead the same error as on staging-next happens.

Since staging-next will soon be merged into master and building crystal with a different stdenv is not straightforward anyway I'm going ahead with merging this.